In debating this incident, one must allow for the "authority" factor of an ATCO in controlled airspace.
The pilot was in a busy flight phase and then received an instruction that he followed.
To Monday Morning Quarterbacks, it is easy to say the ATCO exceeded his authority, but to a busy PPL, there would be a great pressure to obey an authority figure.
We saw this before with the student pilot at SND.
Bad stuff and well done to the reporter, I hope the ATCO involved has been through a retraining regime covering both the relevant law AND human factors.